1. Field of the Invention
This invention relates generally to access devices which include compliant seal material, and more specifically to surgical access devices and methods facilitating maintenance of gel valves during periods of non-use.
2. Discussion of the Relevant Art
Access devices in general are disposed relative to a conduit and are adapted to provide input to a flow of fluid through the conduit. The device will typically is include a valve assembly which controls passage of the fluid in either a liquid state or a gas state. Such access devices may be adapted for use with fluids such as foods, oils, and grease, for example.
Devices of particular interest include surgical access devices which are commonly used to form a passageway across a body wall and into a body cavity or other body conduit. This passageway enables a surgeon operating exteriorly of the body to perform surgical operations within the body conduit by manipulating instruments through the passageway. These instruments might include, for example, scopes, needles, graspers, clamps, staplers, sutures and cutters.
Of course, the passageway, more commonly referred to as a working channel, also provides a path for fluids to exit the body from the body conduit. In order to inhibit this leakage of fluids, some access devices are provided with valves which can seal the working channel both in the absence of the instrument and in the presence of the instrument.
The sealing of the working channel is of particular importance in the case of laparoscopic surgeries where the abdominal cavity is inflated with an insufflation gas in order to distend the abdominal wall and thereby increase the size of the work environment. Trocars are commonly used as access devices for this type of surgery. The trocars include a cannula and a seal housing containing one or more valves which facilitate instrument access while inhibiting leakage of the insufflation gas.
Recently, trocar valves have been formed of highly compliant gel materials such as those disclosed and claimed by applicant in co-pending PCT Application Ser. No. PCT/US01/29682 filed on Sep. 21, 2001 and entitled “Surgical Access Apparatus and Method”, which designates the United States and claims priority from U.S. patent application Ser. No. 60/241,958 filed on Oct. 19, 2000, both of which are incorporated herein by reference. The specific use of these materials as trocar valves is disclosed in PCT Application Ser. No. PCT/US02/15696, which designates the United States and claims priority from U.S. Provisional Application Ser. No. 60/312,683 filed on Aug. 14, 2001. This application, which is entitled “Access Sealing Apparatus and Method”, is also incorporated herein by reference and discloses many embodiments of trocar gel valves which are all applicable to the present invention.
The gel material included in these valves may have a slight degree of cohesion which tends to degrade the function of the valve over long periods of time, such as during storage and prior to use. For example, in an embodiment including a slit formed between mating gel components, a chemical or mechanical bond can tend to form across the slit over an extended period of contact. Of course, it is desirable to inhibit this formation of bonds or otherwise to maintain or recreate the slit prior to use of the trocar.